Presentation
Right knee pain.
Patient Data
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The distal half of the femur is occupied and expanded with a heterogeneous mass with areas of bone formation. Posterior the periosteum is elevated (Codman's triangle).
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Delayed phase bone scan image demonstrates intense uptake in the distal right femur. A single focus of increased attenuation projects just to the right of the sternum inline with the chondral cartilage of the third rib. No other suspicious lesions identified.
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MRI through the lesion demonstrates a soft tissue mass completely replacing the medullary cavity and extending into the adjacent soft tissues. It is low to intermediate in signal on T1 and high on T2 weighted images.
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Distribution of osteosarcomas. The most frequent location is around the knee. Layout and distribution: Frank Gaillard 2009, Line drawing of skeleton: Patrick Lynch 2006, Creative Common NC-SA-BY
This patient went on to have surgery and an osteosarcoma was histologically confirmed.
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A limb sparing resection has been performed. The distal femur and adjacent tibial plateau has been resected and a total knee replacement inserted.
Case Discussion
This case demonstrates relatively typical appearances of a bone forming osteosarcoma of the distal femur (typical location) in a 17-year-old (typical age).